No. 3.— CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY 
OF THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 
COLLEGE, UNDER THE DIRECTION OF E. L. MARK, No. 202. 
Maturation, Fertilization, and Segmentation of Pennaria tiarella 
(Ayres) and of Tubularia crocea (Aqg.). 
By GrorceE T. Harairv. 
TABLE OF CONTENTS. 
PAGE 
Lev Introduction. >... *, Ae ge ee me eg ee CoP 
II. Material and Sepera STO WAT EE a eer maar mer TE (53 
Til.. Observations '’..«. Pe a aah ty” ko gt ap TT te Ch eee rE 
A. Pennaria ett Pe MP re cr oc oie Serra ee eee 
1. Growing eggs ... ~ kl abel EA A A hy AD to Sold 2 
2. Formation of polar baits TAIN, RITE: SOR is EO 
Piieeiiacion Seas ia tO one) 9 CaS 
A Clear asey TA Peek AY oAe GPa Leds Sp lelyt. eee 
Bas itablariavcrocesuccas 2. Aap Speen - pie ss 2 ¢ a | Cigepetlinaeee 
L OURRRSa «al, ahh bie ths hetdsi hwieihicia 490 ene ee 
2. Odcytes BOGE AS SSIES RL A aoe eee BEL oe HE To: 
a. Nueleolus’:.: .. PROT RL, au Milo Sbeney 
3. Polar-cell formation er Beran Ute elas n say oe meee 
ag DSK co ar aeons ee ia SPs ac mms Peg PRU! I 
ae Marly, CLEAVABE yes. yy edt et, eels Sete PRR ate g ot 
b. Later cleavage . . ee SLD EO 
c. The formation of the velin layers Pes EC er a oe 
d. Double nuclei Ky. ati Tt 8 ea om we Fe SZ 
IV. Discussion and historical review ike Shiites, < Uslere 194 
DAE pawdhuol abet. Satie’ Peni to verotenedi Lan? jy poe 
fa peis AME UCM, jet. lWtad ping alt oe | sie tied (ae 
2 ie Poltarceclk fOnMatIOly (ete et ake te ci ousie, Sas ioe ed eee Lod 
Aaa ate CIAL obese! Ae Rites cds, eee eer Ses) at ig lat 2c aa ona OO 
LO e Es uber ee ig oye eee eg Sky s der Lee ee 
GINO mice ees  etecallis tb ger te Soe ae aU 
V. Summary .. ee ee PO ee eet? Ta 
A. meen adsina gh sie ble soy Ca aba taba ct als Wa 203 
1. Nucleolus . . SE ak) Cs’ 3 ative ea abs 
2. Polar cells nies Slesrant lige tie) career . ya b2as 
S. hentdicdticna Prk. hana fasta a a 8) ony“ 
MOS Ol serra a TEM Sie Th alegi sitio, hvd> alas arent ee. ae 
Be ta Faibear ia BPOCCAM a oA or Bch cee a hse odictiads oy ke inde, eee 
1.) Oocytes. ah 3: ON, SORES Re RTE that Pen Ee 1 
a. Germinative one Sh aah ARPA ERE Pet tar case aes Sees pad ernie. 5% 
Bee CIC GUS Me ce ce oe se eh oe gett a ere ot es ee 
